 Water softener systems works in two different ways: 1) by adding a water softening powder after it's is drawn from the faucet; or 2) by the ion exchange process. The reaction between the powder and the impurities is quick.
In the typical whole house water softeners, the water to be treated, which contains calcium ion (Ca2+) and Magnesium ion (Mg2+), is passed through a bed of small plastic beads called zeolite covered with sodium ions. As the water flows past the sodium ions, calcium and magnesium ions then displace the sodium ions. The sodium ions are released from the beads and the calcium and magnesium ions take the place of the sodium ions—ion exchange.
The salt must be replenished periodically. Water softening will no longer take place when all the sodium ions have been exhausted. Therefore, backwashing must take place in order to recharge or regenerate the resin beads. The system is backwashed to loosen resin and to flush out any impurities that may have collected on the beads and the calcium and magnesium ions are released into the backwash water. Some systems are designed for automatic regeneration.
The frequency of regeneration depends on the hardness of the water, amount water to be softened, and the size of the softener. The wastewater generated during the recharge phase of the water softening process mixes with other household wastewater that enters the sewer system, or a septic tank. Benefits of recharging is 1) to make the beads available to remove chemicals which cause water hardness; and 2) to prevent a leakage which can occur when certain sodium to hardness ratio is exceeded thus degrading the effluent quality.
Softener operations can be automatic, semi-automatic, or manual depending on the type of resin regeneration. Automatic water softeners will regenerate on a predetermined cycle either by a clock or the amount of water used. In a semi-automatic operation, regeneration is is operated manually; and in manual softener operation, backwashing, and rising, almost everything is done manually.
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